Many types and designs of power driven cutters for intraocular microsurgery have been developed and used. Such cutters typically incorporate means for extracting severed material, and for the infusion of fluid, and have commonly been of two basic configurations, one configuration being of the end cutting or trephining type, and the other designed for side cutting. Side cutters generally incorporate a closed-end tube having a lateral orifice near its end which functions both as a cutting edge and an infusion inlet and within which a cutter rotates or reciprocates so as to coact with the periphery of the orifice and shear material which penetrates the orifice.
In order to afford the surgeon the greatest possible working range, the cutting orifice, in rotary-type side cutters, is placed close to the distal end; to permit working as close to the retina as possible, for example. With cutters of the axially reciprocatable type it is not possible to place such opening as close to the end as is desirable, due to the room required for travel of the cutter.
Side cutters of the rotary type allow placement of the cutting orifice close to the end, and thus afford a greater range, and have been successfully employed. Great care is necessary, however, to insure that such cutters are always perfectly sharp. If used when even slightly dulled or damaged in the cutting area, there is danger that tissue will be spooled or wound on the rotating cutter.
The overall objective of the present invention is to provide an improved side-action microsurgical cutter-extractor instrument having an oscillatory cutting action.
A related object is to provide such an instrument incorporating a cutting blade portion of segmental cross section, the operating cycle of which commences and ends at a desired position, such, for example, that the orifice is fully open, and the shearing action of which is performed by angular reciprocating travel of less than one full revolution and preferably less than 120.degree., and in the closed position of which the leading edge of the cutter blade slightly overlaps the farther edge of the orifice.
Another object is to provide such an instrument which is convenient to use, simple and reliable, and easy to disassemble to permit sterilization and interchange of cutters.
A further object is to provide such an instrument which is capable of single cycle operation, and which is readily adjustable in such manner as to be operable either in a reciprocatory or a continuously rotatable mode.
Other objects and advantages will become apparent upon consideration of the present disclosure in its entirety.